Physical vapor deposition (“PVD”) systems are used to deposit thin layers of a target material onto a substrate. PVD systems generally include a radio frequency (“RF”) generator that transmits a continuous and/or pulsing signal to a deposition chamber. An RF match having a variable impedance is generally located between the RF generator and the chamber. The RF match may be tuned, i.e., the impedance may be varied, to make the impedance of the RF match be the complex conjugate of the deposition chamber's impedance. Tuning the RF match reduces reflected power from the chamber, thereby increasing the power transferred from the RF generator to the deposition chamber and into the plasma deposition process.
Oftentimes the RF generator is run in pulse mode and transmits a pulsing AC signal to the deposition chamber rather than a continuous AC signal. Conventional RF matches, however, cannot be actively tuned while the RF generator is in pulse mode. Instead, the conventional RF match is tuned while the RF generator is run in continuous mode. Once the RF match is tuned, the impedance of the RF match is fixed, and the RF generator is switched to pulse mode. Although the chamber impedance may vary while the RF generator is running in pulse mode, the RF match impedance remains fixed resulting in reflected power from the chamber. There is a need, therefore, for systems and methods for actively tuning an RF match for a deposition chamber while the RF generator is running in pulse mode.